package com.riant.day01;

import java.util.HashMap;
import java.util.Hashtable;

public class TestMap {
    public static void main(String[] args) {
        testHashTable();
    }

    public static void testHashTable(){

        Hashtable<String,String> hashtable=new Hashtable<>();
        hashtable.put(null,"zhangsan");
    }
}
